Input output file c programming

Card number or PIN is invalid. Any help is appreciated. Improve this question. David Cober David Cober 15 4 4 bronze badges. Sounds reasonable. So why don't you try it? What specific problem or missing knowledge is blocking you? That is, in addition to describing the task you need to describe one specific issue you have that you would like answered here.

Does it help to know that you can use fgets to read a line from file, strtok to extract each field and atoi to convert from string to integer? Here is a version with fscanf: onlinegdb. Using fgets to read lines and a non-destructive parser sscanf possibly — not strtok because it is destructive to check whether the lines match. The C programming language provides standard library functions to read any given input and to display data on the console.

Before moving forward with input and output in C language, check these topics to understand the concept better :. Compile and Run C Program. The functions used for standard input and output are present in the stdio. Hence to use the functions we need to include the stdio.

In C Language, computer monitor, printer, etc. The printf function is the most used function in the C language. This function is defined in the stdio. This function is used to print a simple text sentence or value of any variable which can be of int , char , float , or any other datatype.

To understand the complete code and structure of a basic C language program, check Hello World Program in C.

Inside the printf function we have used a single quotation , it will work fine because we have used double quotation outside. In the code example below, we have used the printf function to print values of a float and double variable.

As you can see in the code example above, we can do formatting as well while printing values of multiple variables using the printf function. To print values of different datatypes using the printf statement, we need to use format specifiers , like we have used in the code examples above.

Also, when we take input from user using the scanf function, then also, we have to specify what type of input to expect from the user using these format specifiers.

When we want to take input from the user, we use the scanf function. When we take input from the user, we store the input value into a variable. The scanf function can be used to take any datatype input from user, all we have to take care is that the variable in which we store the value has the same datatype.

If we have to take an integer value input from the user, we have to define an integer variable and then use the scanf function. Just like integer value, we can take input for any different datatype.

Let's see an example for float type value. Try doing the same for taking a double type value as user input. The printf function returns the number of characters printed by it, and scanf returns the number of characters read by it.

In this program printf "studytonight" ; will return 12 as result, which will be stored in the variable i , because the word studytonight has 12 characters. The first printf statement will print the statement studytonight on the output too. C Language C Tutorial. C Compiler. Standard Template Library. Python Python Tutorial. Python Programs. Python How Tos. Numpy Module. Matplotlib Module.

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Java Wrapper Class. Java 8. Java More in Java Improve Article. Save Article. Like Article. PrintStream ps. InputStream is. BufferedWriter new FileWriter "output. For getting input from input.